Method and means for introducing alloying material



1941- J. s. KIRKHAM 2,260,226

METHOD AND MEANS FOR INTRODUCING ALLOYING MATERIAL Filed Dec. 31, 1940 Petented Oct. 21, 1 941 METHOD AND MEANS FOR INTRODUCING ALLOYING MATERIAL John S. Kirkham, Waterloo, New South, Wales,

Australia, assignor to Mechanite Metal Corporation, Pittsburgh, Pa., a corporation of Ten- Application December 31, 1940, Serial No. 372,660

2 Claims.

This invention relates to a method and means for introducing powdered or granulated alloying metal into molten metal and its purpose is to achieve thorough dispersion and assimilation of the alloying metal without waste of the latter.

Heretofore alloying metal in powdered form has been added to the molten stream in the usual spout, but in such practice the added material tends to wash on the surface and may become contaminated with the slag and scum that forms on the surface of the metal in the ladle. This method is, therefore, wasteful and inemcient I have found that by flowing the melt in a manner to create a vortex over an escape opening and by dropping the powdered alloying metal directly onto the surface of the swirling metal at the vortex, thorough distribution of the alloying metal in the melt is obtained, solution of the alloying metal taking place in the vortex, as the melt drops from the vortex through the escape opening, and being rapidly completed in the ladle under the agitation set up in the latter by the drop thereto. In adding the alloying metal in this new manner, I am able to effect savings in alloying materials as high as fifty per cent over the prior method wherein the materials were fed into the metal in the spout.

In carrying out the invention, I provide a well or bowl into which the spout delivers tangentially so as to give a swirling effect in the bowl. The bottom of the bowl is provided at the vortex with an opening through which the melt passes to the ladle. A mechanical feeder is preferably provided for feeding the alloying metal accurately into the vortex. Apparatus of this nature is shown by way of example in the accompanying drawing to which reference will now be made.

In the drawing:

Figure 1 is a perspective view of a cupola equipped in accordance with the present invention.

Figure 2 is a plan view of the bowl and the adjacent end of the associated spout, these elements appearing also in Figure 1.

Figure 3 is a section substantially on line 3-3 of Figure 2.

Figure 4 is an elevation, partly in section, of feeding mechanism, and

Figure 5 is a section substantially on line 5--5 of Figure 4. v v

Referring to the drawing, reference numeral I0 I designates a portion of a cupola having a downwardly inclined discharge spout ll provided at its lower end with a flange l2 to which is bolted the flange l3 of the bowl H.

walls of the bowl are circular, and its throat I5 is in direct continuation of the spout II. The throat is generally tangential to the bowl and the latter has a bottom wall provided with an escape opening l6 which is eccentrically disposed so as to be out of the line of the throat and coincident with the vortex which forms as the result of the swirling effect given the molten metal due to its tangential influx. The bottom wall of the bowl is preferably horizontal and its side walls vertical. It will be evident that the bowl can be readily applied to or removed from the end of the spout i l.

Reference numeral ll designates a shelf having a vertical bearing it which rceives a vertical bar secured at its ends in top and bottom bearings 20 andv M on the cupola. The bearing is is swingable about the bar l9 and its weight is supported on the bearing 2i. The height of the shelf can be varied by interposing spacer means between the bearings i8 and 2!.

A motor 22 on the shelf ii is adapted-to drive a horizontal shaft 23 through a speed reducer 24, and this shaft has its free end journalled in a bearing block 245. In a cavity in the bearing block a cupped feed wheel 25 is fixed on the shaft 23 and is adapted to feed powdered alloying materials from a hopper 26 to a tubular chute comprising upper and lower telescoped portions 21 and 28 which are adapted to be secured in adjusted relation by means of a screw 29, A slide valve 30 at the bottom the hopper is adapted to control or shut off feed from the hopper to the wheel The valve is operable by a lever 25 which cooperates with a graduated are 32 in a manner to indicate the rate of feed for which the valve is set. a

The free end of chute portion 28 is bent to xtend directly downwardly and has a tapered extremity 33. By swinging the shelf, by swinging chute 28 relative to portion 27, their interengaged parts being cylindrical, and by adjusting portion 28 longitudinally of port on 21, the extremity of spout 23 can be spotted directly above, or suitably adjacent escape opening lb of the bowl l4 and above the metal in the latter.

In use, molten metal M, here assumed to be iron, will be flowed down the spout H and into the bowl I4, swirling in the latter and forming a vortex on a vertical axis over the opening It as indicated in Figures 2 and 3. Alloying material, such as ferrosilicon, calcium silicon, nickel, chrome, and so forth, in the hopper 26 is fed from the latter at the desired rate by the wheel As most clearly shown in Figure 2, the side 25, and is directed by the nozzle 83 into the swirlcent of the flow period.

ing metal at the vortex as indicated at A, Figure 3, coming directly into contact with the surface of the metal so as to be effectively distributed and assimilated as the mixture escapes through the opening ii and drops to the ladle II. Any scum inthe bowl It tends to be thrown toward the lateral walls of the bowl, the nozzle 83 delivering the alloying material to the clean metal directly at or suitably adjacent the vortex. 3 The alloying material commences to dissolve as I soon as it strikes the metal in the bowl, dissolution continuing during flow to the ladle and being quickly and effectively completed in the ladle,

the ladle being sufliciently below the bowl so that considerable turbulence is caused therein by the arriving mix. A strong dispersing or distributing action is present at the vortex and continues throughout the assimilating process, resulting in high uniformity of the mix in the ladle. A large saving in alloying material is efl'ected, as heretofore mentioned.

The alloying material may be fed continuously at adjusted rate during flow from the cupola and preferably it is added during at least fifty per vertical swirling axis from which axis the stream falls to the ladle. and dropping the alloying metal directly onto the surface of the molten metal substantially at the axis of the vortex.

2. Apparatus for introducing powdered alloying metal into molten metal which comprises the combination with a furnace spout, of a bowl at the discharge end of said spout so arranged with respect to the line of flow from the spout that a vortex is formed in said bowl on a vertical axis when said spout discharges into said bowl, said bowl having a bottom discharge opening at said vortex, and means for dropping powdered alloying metal directly onto the surface of the molten metal substantially at the axis of the vortex.

' J. S. KIRKHAM. 

